#include <iostream>

using std::cin;
using std::cout;
using std::endl;
using std::string;

int main() {
    // for
    string word1 = "some string";
    auto word1_size = word1.size();
    for (decltype(word1_size) i = 0; i < word1_size; i++) word1[i] = 'X';
    cout << word1 << endl;

    // while;
    string word2 = "some string";
    auto word2_size = word2.size();
    decltype(word2_size) j = 0;
    while (j < word2_size) {
        word2[j] = 'X';
        j++;
    }
    cout << word2 << endl;
    return 0;
}